Logical ReasoningDifficulty: Medium

PT115 S2 Q7 Explanation

The kind of thoughts that

A free, expert breakdown of this official LSAT Logical Reasoning question.

TopicsNecessary Assumption

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Stimulus

The kind of thoughts that keep a person from falling asleep can arise in either half of the brain. Therefore, a person being prevented from sleeping solely by such thoughts would be able to fall asleep by closing the eyes and counting sheep, because this activity fully occupies the left half of the brain with imagining sheep, thereby excluding the sleep-preventing thoughts.

What this question is testing

Necessary Assumption

Your task

Find the assumption the argument requires in order for its conclusion to hold.

Common trap

Answers that would help the argument but aren't strictly required (sufficient, not necessary).

Winning move

Negate each choice — the right one breaks the argument when negated.

Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.

The question
7.

According to the hypothesis, for a person to use counting imaginary sheep as an effective method of inducing sleep, which one of the

Answer choices

  1. Too Strong: wide variety3% picked this

    The person is able to imagine a wide variety

    This technique only assumes that a person is able to imagine sheep.

  2. Too Strong: normally7% picked this

    The person normally has a difficult time

    This technique only assumes that someone is having trouble falling asleep purely because of thoughts arising in the brain. It doesn't matter whether that person normally has a difficult time falling asleep or only occasionally has a difficult time falling asleep.

  3. Correct77% picked this

    Thoughts of sheep would not keep the person awake at

    Why this is right

    Yes, this technique assumes that thinking of sheep will not keep the person awake. If thoughts of sheep would keep the person awake, then obviously this technique wouldn't help someone fall asleep. Even though this question stem doesn't resemble typical Necessary Assumption questions, if we recognize it as a "Which of these answers is necessary in order for X to work", then we know we can use the Negation Test (i.e. the Necessity Test) to judge these answers. And if we're using our Necessary Assumption brain to judge these answers, we would think, "Be wary of strong language; be attracted to ruling-out language (not)".

    Skill tested: Necessary Assumption · how this choice captures the argument's function is the move to repeat next time.

  4. Too Strong: whenever13% picked this

    Thoughts of sheep would induce sleep in the person whenever those

    This technique doesn't need to assume that "whenever someone thinks of sheep, it will induce sleep". That would be very scary while driving! "Don't think of sheep. Don't think of sheep." This technique is assuming that combining thoughts of sheep with counting can enable someone to shut off the thoughts that are preventing them from sleeping. But the technique doesn't assume that thoughts of sheep, by themselves, induce sleep.

  5. Out of Scope: dream content0% picked this

    Thoughts of sheep rarely, if ever, arise in the

    The technique doesn't need to assume anything about what sorts of images or topics we see in our dreams. This technique is just about helping us to fall asleep. Once we're asleep, it's our subconscious's job to figure out what we should dream about.

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